Internal combustion engine



Nov. 7, 1933.

R. s. THWAITE INTERNAL COMBUSTION ENGINE- .Filed June 29, 1929 2 Sheets-Sheet 1 Nov. 7, 1933.

R. s. THWAITE INTERNAL COMBUSTION ENGINEf Filed Jun 29. 1929 '2 Shets-'Shee 2 xww INVENTOR #QM ATTORNEYS.

Patented Nov. 7, 1933 2 Claims.

ihis invention relates to internal combustion engines, and has particular reference to improved valves and valve mechanisms, for example, for gas engines used in automobiles.

An important object of the invention is to provide a compact valve system which will give quicker and fuller port openings than has been possible with the commonly employed valves of the pop pet type.

Another object is to provide valves which will be smooth and. silent in operation and thereby make possible greater engine speeds.

Another object is to provide a system of balanced valves which may be easily and quickly inspected, repaired, or replaced without requiring complete dismantling of the engine.

Another object is to provide such a valve systern which will be simple in construction, strong and durable in service, and eificient in operation.

With the foregoing and other objects'and advantages in view, the invention'resides in the novel features of combination, construction and arrangement set forth in the hereinafter following description or shown illustratively in the accompanying drawings.

In the accompanying drawings:

Figure l is a top plan view of ages engine embodying the invention, broken open in section at the first or front valve of this invention.

Fig. 2 is a side elevation of the same broken away in section through the housing at the first valve, and at the exhaust ports at the other valves.

Fig. 3 is a vertical section on the line 3-3 of Fig. 4 is a front end elevation of the engine, with the housing partly broken away in section to show the driving connections for the valve mechanism.

Fig. 5 is a fragmentary bottom plan view of the cylinder head. v

Fig. 6 is a vertical section taken on the line 6-6 of Fig. 1, looking from the rear.

Fig. 7 is a vertical section taken on the line 7-? of Fig. l,looking from the front.

Figs. 8, 9, 1c and ll are successive diagrams, in rear elevation like Fig. 6, showing the relative positions or the valve parts at certain points in the cycle of the engine.

The invention has been illustrated for convenience as applied to a four-cylinder four-cycle automotive engine, but its utility 'is not restricted .to this specific application. The engine cylinders 10 are shown arranged in line, formed in a unitary casting, and at their lower ends connected (ill. l23===ll88) with a crank case 11 of any ordinary or preferred design. Slidable within the cylinders 10 are pistons 12, connected by rods 13 with a crankshaft 1d, journalled in the crank case 11. The-upper ends of the cylinders 10 are covered by cylinder heads 15, which preferably are cast in a single head casting closing all of the cylinders of the engine, and said multiple head is shown detachably secured to the unitary cylinder block by means of studs or bolts 16. Water jackets 17 provide circulation passages surrounding the walls of the respective cylinders 10 for the circulation of a cooling fluid, such as water, and similarly, jackets and passages 18 are provided in the cylinder head 15 for maintaining cool said head and associated valves. v

Valve casings 19 are formed upon or secured to the cylinder head 15, there being one such casing for each cylinder in the illustrated embodiment. These are formed to constitute slideways to receive the movable valve parts to be described. Since the valve casings and valves may be alike for each cylinder, only one of them will be described in detail. Each slideway 19 at its outer or left end is shown closed by a removable plug or cap 20, so that when opened the movable valve members to be described may be assembled and disassembled through the opening. 1

Each valve casing is formed with a substantially central bore 21, which constitutes a slideway preferably disposed at an angle, namely, at a right angle to the length of the corresponding cylinder or piston stroke. Also, while different arrangements are available, the illustrated embodiment has such bores offset laterally with respect to the axes of the cylinders, so as to condense the structure and better accommodate spark plugs. At the upper or outer side of each valve casing is an inlet port 22 and an outlet or exhaust port 23, shown equidistantly spaced from the center of the cylinder. Said ports furnish communication between the bore 21 and inlet and outlet manifolds 24k and 25 respectively. In line with the ports 22 and 23, but at the lower or inner side of the bore 21 are ports 26 and 27, which furnish communication between the bore 21 and the interior of the corresponding cylinder 10. Such communications however, are adapted to be alternately opened and closed for the purpose of controlling the passages of gases to and from the interior oi the cylinder ill at definite periods, according to the cycle of the engine. The fixed upper or outer intake port 22 and the fixed inner or lower intake port 26 are shown in transverse alinement, but might be out oi line,

depending on the disposition of the movable ports to be described; and similarly with the fixed outer and inner exhaust ports 23 and 27.

A tubular valve member or barrel 30 is slidingly fitted within each fixed slideway or bore 21, and is provided at its upper or outer side with inlet and exhaust ports 31 and 32, and at its lower or inner side with corresponding inlet and exhaust ports 33 and 34. The ports 31 and 33 are shown in transverse or vertical alinement, as are the ports 32 and 34 to coordinate with the disposition of the ports yet to be described.

The distance between said alined pairs of ports, that is between the ports 31 and 32, or 33 and 34, is different from and preferably less than the distance between the fixed ports 22 and 23, to enable the ports to be opened and closed at different times in the engine cycle. The length of the tubular valve or barrel 30 is considerably greater than the distance between the ports 22 and 23, so that the ends of the valve never pass beyond so as to uncover any of the ports 22, 26 or 27. In fact, a substantial lap is provided, as shown in Fig. 6, so as toprevent leakage outside of the valve barrel 30, and such lap being sufficient toallow of the use of a packing or sealing ring if desired.

Slidingly fitted within the tubular valve or barrel 30 is a second movable valve member or slide 36, which may be tubular for lightness and provided with cross walls or partitions 37 and 38, enclosing valve passages. This valve slide 36 also has in its upper or outer side an inlet port 39 and an exhaust port 40, and in its lower or inner side corresponding inlet and outlet ports 41 and 42. The ports 39 and 41 are preferably in vertical or transverse alinement, and communicate with each other through a transverse valve passage 43 defined between the walls 37, 37. Similarly the ports 40 and 42 are shown in vertical alinement with each other and communicate through a passage 44 between the walls 38, 38. The passages 43 and 44 are shown at right angles to the length of the valve, but might be inclined or of other shape, coordinating with the ports of the other valve members. The distance between the respective pairs of ports 39, 41 and 40, 42 in the interior slide 36 is substantially different from or greater than the distance between the ports 31, 33 and 32, 34 in the barrel 30, thus providing a desirable arrangement of lap and lead of said ports with respect to each other. The spacing between the ports in slide 36 may substantially equal the spacing of the fixed ports, as shown.

The four sets of valve parts for the four cylinders may be actuated by a common mechanism .in harmony with the engine cycle, for example by the following described constructions. At one side of the engine, the cylinder head is shown extended beyond the ends of the valve casings 19, as a housing 45, shown in Figs. 6 and 7, to

provide an enclosure 46 for the actuating mechanism. vIn the enclosed space 46 is shown a valve shaft 47, said shaft extending longitudinally and having two cranks or offsets 47* and 47 for each set of valve members. The two cranks for each valve set are angularly spaced apart, for example by 60, as shown in Figs. 6 to 11, and are connected respectively by connecting rods 48 and 49, and connections 50 and 51 with the valve members 30 and 36. The connection at 50 between the connecting rod 48 and the tubular valve barrel 30 is shown as a pin or stud 50 which extends radially outward from the side of the valve memher; and to insure parallel motion the valve end of the connecting rod 48 is shown guided in a groove 53 formed in a fixed extension or wall 54 of the casing 19. This or other arrangement may be so constructed as to permit the barrel 30 to be disconnected and removed through the far end of the casing when the cap 20 is removed.

As the valve crankshaft 47 is rotated, the respective valves 30 and 36 of each cylinder will be caused to reciprocate in timed relation to the movements of the corresponding piston, such movements being timed to open and close the ports according to the cycle of the engine. The valve sets for the several engine cylinders are actuated in different timing due to the sequence of operation of the respective pistons, for example the usual sequence l, 3, 4, 2.

In order to rotate the valve actuating shaft 47 in properly timed relation to the movements of the pistons 12, mechanism may be provided such as is best shown in Figs. 2 and 4. Such mechanism comprises a pinion 55 secured to the end of the crankshaft 47, which pinion meshes with an idler or trundle gear 56 which takes its rotation from the engine shaft as will be described. While the shaft 47 and pinion 55 are mounted in the removable headcasting extension 45, the idler 56 and connections driving it are preferably mounted in a housing 57 formed at the front end of the cylinder block. Said idler gear 56 is freely rotatable at the end of an adjustable carrying arm 58 which is mounted loosely upon a shaft 59, which shaft carries a pinion 60, which drives said idler 56 and thereby the pinion 55 and valve shaft. The shaft 59 also carries a sprocket wheel 61 driven by a silent link sprocket chain 62 extending from a sprocket Wheel 63, which in turn is mounted on an intermediate shaft 64, which carries another sprocket wheel 65, the latter connected and driven by a sprocket chain 66 from a sprocket wheel 67,'rotated by or carried on the main crankshaft 14. The arrangement of sprocket wheels is such that the valve actuating crankshaft 47 rotates in a two to one ratio with the main crankshaft 14, so that the valve shaft turns once for each four piston strokes. The housing 57 is shown extending down to enclose elements 58 to 67.

It will be clear from the foregoing that the driving connection which exists between the engine shaft 14 and valve shaft 47 is readily disengageable to permit the cylinder head casting to be removed, namely by the mere lifting of the head, with the shaft 47 and pinion 55, the latter disengaging the idler 56, all without necessitating any disconnection or dismantling of any of the other driving mechanisms. This important feature permits easy removalof the complete cylinder head and valve sets as a unit, it only being necessary to set the pinions 55, 56 and to reengage in their correct relation when reassembling, guided by index marks thereon. The adjustability of the idler 56 makes possible an exact compensation for any variations which might exist in the distance between the centers of the shafts 47 and 59.

Above each of the cylinders 10, the cylinder head 15 is provided with openings 70 for the accommodation of spark plugs 71, said openings being preferably disposed between the corresponding ports 26 and 27, as best shown in Figs. 1, 3 and 5, and preferably flared at their inner ends, to reduce any likelihood of the spark plug being fouled from carbon deposits or the like.

Referring to the diagrams, Figs. 8 to 11, the

complete cycle of one cylinder will be explained. In Fig. 8 the parts are shown in the relative positions which they occupy at the beginning of the firing or power stroke. The piston 12 is commencing to descend in the cylinder 10, and the respective fixed intake and exhaust ports 22, 26

and 23, 27 are completely cut 01? from communication with each other with ample lap. The valve shaft 47 is rotating in a counterclockwise direction, as viewed in these diagrams, from which it will be seen that the valve slide 36 has reached the limit of its movement toward the right, whereas the valve barrel 30 is still moving toward the right, as indicated by the arrow. The expansion of the gases within the cylinder 10 forces the piston downwardly in the usual manner, and as it reaches the lower end of its stroke, while both valve members 30 and 36 are moving leftward, the ports 23 and 27 become uncovered and come into communication with each other through ports 32, 4c, 34 and 42, whereby to permit exhaust oi the burnt gases. By virtue of the relative movement of the two valve members, the full opening of the exhaust ports is not attained until as shown in Fig. 9 the piston has ascended a substantial distance in its exhaust stroke. The exhaust ports will not be wholly closed until the piston has reached the upper end of its stroke.

As the piston begins to move downwardly for its intake stroke, the intake ports 22 and 26 commence to open, but not reaching their full open position until the piston is substantially about half way down, as shown in Fig. 10. The fresh charge of fuel thus drawn into the cylinder is compressed during the next upward or compression stroke of the piston, throughout which all the ports are kept efiectively closed, as will be clear from Fig. 11 in which the ports have just closed, and the piston is about to start up. Thereafter the described cycle is repeated.

An improved valve system has thus been described for internal combustion engines, wherein wide port openings and well lapped closings are quickly efiected and maintained at the proper points in the cycle, afiord high engine eficiency. Not only is emciency increased with this valve system, but smoothness of action and quietness are enhanced. Owing to the cylindrical or barrel shape of the valve members, with the intake and exhaust entering each member at one side and leaving at the opposite side, the pressures are fairly balanced, the valve movements "are easy and smooth, and wear is negligible,so that maintenance costs are reduced.

A further advantage of the invention is that it can either be applied to existing engines without changing the cylinders or permanent parts, or can be built directly into an engine, with the benefit, in either case, of ease of access, adiustment, repair and replacement of the valve mechanismor its parts, and without sacrificing the other advantages referred to.

Among available modifications are that the valve slide 36 may be a cast cylinder, apertured tor the passages 43 and 44 and the ports, instead of a tube with partitions. The sprockets, chains, and gears disclosed for driving the crankshaft 47 may be in various arrangements, or may be replaced for example by shafts and bevel gearing. Various other changes in matters of combination,

construction, and arrangement of parts may be made within the principles of the invention, and no limitation to such matters is intended except to the extent set forth in the appended claims.

ciprocable in each valveway of the common cyl- What is claimed is:

1. In a multiple cylinder internal combustion engine, a common cylinder block containing a plurality of open-top cylinders in longitudinal line and with pistons therein connected with the cranks of an underneath crankshaft; a longitudinal unitary cylinder head common to and closing the top ends of said plurality of cylinders, such head being unitarily detachable and attachable, and formed with a plurality of separate transverse cylindrical valveways, one for each cylinder, and with fixed inlet and exhaust ports between each valveway and its cylinder and between each valveway and passages of supply and exhaust, and such passages of supply and exhaust; valve means for the several cylinders comprising separate cylindrical valve barrels, one reciprocable in each valveway of the common cylinder head, and a valve slide reciprocable in each barrel, with operating movements transverse to the length of the engine, said barrels having ports cooperating with said fixed inlet and exhaust ports, and said slides having ports cooperating with said barrel ports; each said valveway having a fixed'longitudinal guideway and its valve barrel having a projection engaging and sliding on such guideway and preventing rotation of the barrel during reciprocation; valve operating mechanism comprising a longitudinal valve shaft turning in bearings mounted upon and detachable bodily with the unitary cylinder head, said yalve shaft having separate pitmen to operate the several valve means in rotation andto operate the barrel and slide of each valve means in diflferent timing,

inlet and exhaust ports cooperatively with the movements of the corresponding pistons; and driving connections from the crankshaft to the valve shaft including a readily disengageable connection permitting the detachment of the cylinder 1 5 head with valve shaft without disturbing the devices by which the valve shaft operates the valve means.

2. In a multiple cylinder internal combustion engine, a common cylinder block containing a 3293 plurality of open-top cylinders in longitudinal line and with pistons therein connected with the cranks of an underneath crankshaft; a longitudinal unitary cylinder head common to and closing the top ends of said plurality of cylinders, such head being unitarily detachable and attachable, and formed with a plurality of separate transverse cylindrical valve-ways, one for each cylinder, and with fixed inlet and exhaust ports between each valveway and its cylinder and be- 3139 tween each valveway and passages of supply and exhaust, and such passages of supply and exhaust; valve means for the several cylinders comprising separate cylindrical valve barrels, one m inder head, and a valve'slide reciprocable in each barrel, with operating movements transverse to the length of the engine, said barrels having ports cooperating with said fixed inlet and exhaust ports, and said slides having ports cooper- Mil ating with said barrel ports complementary guide means on each valveway and its contained valve barrel respectively, permitting reciprocation while preventing rotation of the valve barrel; valve operating mechanism comprising a com- 1% mon longitudinal valve shaft turning in bearings mounted upon and detachable bodily with the unitary cylinder head, said valve shaft having connectors or pitmen to operate the several valve means in rotation and to operate the barrel and slide of each valve means in different timing, for causing the opening and closing of the several inlet and exhaust ports cooperatively with the movements of the corresponding pistons; and driving connections from the crankshaft to the valve shaft including a disengageable connection permitting the detachment of the cylinder head with valve shaft without disturbing the connectors by which the valve shaft operates the valve means.

3. In a multiple cylinder internal combustion engine, a common cylinder block containing a plurality of open-top cylinders in longitudinal line and with pistons therein connected with the cranks of an underneath crankshaft; a longitudinal unitary cylinder head common to and closing the top ends of said plurality of cylinders, such head being unitarily detachable and attachable, and formedwith a plurality of separate transverse cylindrical valveways, one for each cylinder, and with fixed inlet and exhaust ports between each valveway and its cylinder and between each valveway and passages of supply and exhaust, and such passages of supply and exhaust; valve means for the several cylinders comprising separate cylindrical valve barrels, one reciprocable in each valveway of the common cylinder head, and a valve slide reciprocable in each barrel, with operating movements transverse to the length of the engine, said barrels having ports cooperating with said fixed inlet and exhaust ports, and said slides having ports cooperating with said barrel ports; and valve operating mechanism comprising a longitudinal. valve shaft turning in bearings mounted upon and detachable bodily with the unitary cylinder head, said valve shaft having separate pitmen to operate the several valve means in rotation and to operate the barrel and slide of each valve means in different timing, for causing the open ing and closing of the several inlet and exhaust ports cooperatively with the movements of the corresponding pistons; each said valveway having a longitudinal guideway and its valve barrel having a wrist-pin for its operating pitman and such wrist pin engaging such guideway to prevent rotation of the barrel.

4. In a multiple cylinder internal combustion engine, a common cylinder block containing a plurality of open-top cylinders in longitudinal line and with pistons therein connected with the cranks of an underneath crankshaft; a longitudinal unitary cylinder head common to and closing the top ends of said plurality of cylinders, such head being unitarily detachable and attachable, and formed with a plurality of separate transverse cylindrical valveways, one for each cylinder, and with fixed inlet and exhaust ports between each valveway and its cylinder and between each valveway and passages of supply and exhaust, and such passages of supply and exhaust; valve means for the several cylinders comprising separate cylindrical valve barrels, one reciprocable in each valveway of the common cylinder head, and a valve slide reciprocable in each barrel, with operating movements transverse to the length of the engine, said barrels having ports cooperating withsaid fixed inlet and exhaust ports, and said slides having ports cooperating with said barrel ports; each valve barrel being adapted to operate in its valveway, and each valve slide in its valve barrel, by reciprocation without rotation therein; valve operating-mechanism comprising a common longitudinal valve shaft turning in bearings mounted upon and detachable bodily with the unitary cylinder head, said valve shaft having connectors or pitmen to operate the several valve means in rotation and to operate the barrel and slide of each valve means in different timing, for causing the opening and closing of the several inlet and exhaust ports cooperatively with the movements of the corresponding pistons; and driving connections from the crankshaft to the valve shaft including a disengageable connection permitting the detachment of the cylinder head with valve shaft without disturbing the connectors by which the valve shaft operates the valve means.

ROBERT SMITH THWAITE. 

